Input type issues in using `Translator` to translate from VRS

This code here tries to subscript into `models`, which is a module, on line 132. This obviously leads to an error:

https://github.com/ga4gh/vrs-python/blob/f38cbca9a4bd7142280149eeea051ddc9c628934/src/ga4gh/vrs/extras/translator.py#L125-L135

I think a bigger problem is inconsistency about expected inputs. The other translators take variant expressions as strings, but translating from VRS seems to try to handle either dicts or Pydantic objects (realistically, probably actually PythonJsonSchemaObjects, not Pydantic). I think it'd be better to maybe expect input to be a JSON object serialized into a string, just to remain consistent and avoid these kinds of issues.